If the voltage is fixed, the using Ohms law: V=IxR If R increases, then the current will decrease proportionally.
Resistance.
A parallel branch is a current path. In general, current follows paths, voltage drops across components, and resistance is the voltage divided by current of specific circuit elements.
Simply add all of the component's resistances together and that will give you circuits total resistance. If you're dealing with a 'series-parallel', or 'parallel' circuit, the equations will change, but in a simple series circuit, the total resistance is just the total of all the component's resistance.
* resistance increases voltage. Adding more resistance to a circuit will alter the circuit pathway(s) and that change will force a change in voltage, current or both. Adding resistance will affect circuit voltage and current differently depending on whether that resistance is added in series or parallel. (In the question asked, it was not specified.) For a series circuit with one or more resistors, adding resistance in series will reduce total current and will reduce the voltage drop across each existing resistor. (Less current through a resistor means less voltage drop across it.) Total voltage in the circuit will remain the same. (The rule being that the total applied voltage is said to be dropped or felt across the circuit as a whole.) And the sum of the voltage drops in a series circuit is equal to the applied voltage, of course. If resistance is added in parallel to a circuit with one existing circuit resistor, total current in the circuit will increase, and the voltage across the added resistor will be the same as it for the one existing resistor and will be equal to the applied voltage. (The rule being that if only one resistor is in a circuit, hooking another resistor in parallel will have no effect on the voltage drop across or current flow through that single original resistor.) Hooking another resistor across one resistor in a series circuit that has two or more existing resistors will result in an increase in total current in the circuit, an increase in the voltage drop across the other resistors in the circuit, and a decrease in the voltage drop across the resistor across which the newly added resistor has been connected. The newly added resistor will, of course, have the same voltage drop as the resistor across which it is connected.
By Kirchhoff's Voltage Law, the sum of the voltage drops around the series circuit will equal the voltage applied to the circuit.
there is 120V across the circuit.
A well designed circuit should be able to operate over a range of voltages, not just at one voltage. Especially a circuit which is intended to be powered by a battery. As the battery starts to get used up, and the voltage drops, you want the circuit to operate as planned.
there is 120V across the circuit.
For a series circuit, the applied voltage equals the sum of the voltage drops
First calculate your resistance for your parallel circuit using the reciprocal formula1/1/r1+1/r2 etc... Get that total and then add it to your resistance total of your series circuits. Divideyour applied voltage EA by Resistance Total RTthis gives you your current total or IT. Calculate your voltage drops by multiplying IT by your resistors in the series circuit. Subtract those voltage drops from your applied voltage EA and you now have your voltage drops for your parallel circuit, which all are equal to each other.
Yes.
Use thevenin model for the output of the power supply. That means there is a voltage source Vs, output resistance Rs and the series load RL which is a short with a resistance value equal to zero ohms. So, voltage across it is zero. The full voltage drops across the resistance Rs according to KVL.